The invention is based on a packaging machine as generally defined hereinafter. In a packaging machine of this kind, proposed in U.S. patent application Ser. No. 653,624 also assigned to the assignee of this application, a control unit computer directs the adsjustment of the various convertible components of the packaging machine when a change in the format is to be made. In particular, the computer controls a motor-driven tool in accordance with stored adjustment values such that the components to be adjusted are each put into a position that matches the format to be used. For adjusting the components, an operator who guides the mobile tool is instructed by the computer via a monitor to approach specific conversion points, which are provided with an identifying number, and couple the mobile tool to the adjusting screw of the particular conversion point. In a packaging machine embodied in accordance with this proposal, there is the danger than an inexperienced operator may mistakenly approach the wrong conversion point, thereby moving its adjustable component to the wrong position. When the machine is later put into operation, this may result not only in the destruction of the packaging material being used, but in breakage and other damage to parts of the machine as well.